The excited cries of children seem to rattle the mesh of the public courts in King's Park.

Judy Murray smiles. She is at home and not just because about 150 aspiring children are playing a few miles from where she learned the game in Dunblane. This is the sort of morning that inspires her as a coach and personality.

"It is great when you look across the net at a young girl and she realises that she has just taken part in her first rally," says Murray. "I love the game and I love seeing others enjoy it too."

This obvious passion is transmitted to children as young as five and the lightness of mood contrasts strongly with the fabricated image of Murray as a stressed mother sitting in the player's box on Centre Court. This has led to a series of portrayals that have traduced Murray as a single-minded mother pushing her son on to success.

She has undoubtedly a drive that may best be summed up by her always seeing good as the enemy of excellent. However, the horrible secret about Murray is that she is funny, self-deprecating and more concerned with the well-being of both her sons than about the number of trophies on the mantelpiece.

"Sometimes it can be tough," she says of the criticism. "It is strange reading something about myself and my personality by someone who has never met me. They see me on the box and think I am intense or strict and severe. Anybody who knows me knows that I am not like that.

"I have been coaching for 20 years and I have never lost my love of the game and I have fun doing what I am doing."

This enjoyment is obvious at King's Park. The courts are, of course, full.

Adam Brown, Central Scotland District Coach and Stirling Tennis Club head coach, had the idea of opening up the courts for free tuition for five to 10-year-olds and invited Murray and Katharine Brown, a former Miss UK who is a more than decent tennis player, to the public courts to help out.

The Murray factor ensured that it was a busy morning. The key question is whether that can now be translated into an enduring, successful future for Scottish tennis. Judy Murray is typically animated on how this revolution can and should be effected.

"Every year after Wimbledon there is a surge of people wanting to play tennis, this year more than ever," she says. "We must plan for this and capitalise on it."

The biggest obstacle is the lack of outdoor courts. "They have been taken away and used for car parks or whatever and now we have a boom in people wanting to play. But we have large towns with no public courts and those are crucial because when you are a beginner you are reluctant to just turn up at a local club. You want to try it out first in a relaxed atmosphere."

She points out that she was giving a coaching session at an Edinburgh public school recently and it had 18 outdoor courts, more than the whole of Stirling.

"We need more places to play, places that are accessible and affordable," she says. "Courts should be opened for free, courts that have fallen into disrepair must be upgraded, school courts should be available during the holidays."

She adds: "We should have more people on the ground . . . students, teachers, volunteers. It does not have to be structured coaching. It just has to be fun."

She knows the Murray factor is already producing a stream of talent, particularly among the girls with Maia Lumsden, Anna Brogan, Emma Devine, Ali Collins and Anastasia Mikheeva all at the forefront of their age groups.

Murray welcomes this progress but immediately focuses on the next step for these talents, saying they must be developed by specialised coaching, most probably abroad.

However, she is no narrow promulgator of elitism. "It is way more important to grow the game, get more kids playing. First and foremost, they must learn to love the game and keep coming back, because if they don't like it they won't. The fun element is crucial. Of course, it becomes more serious as they rise through the ranks."

She adds: "It is important, too, that they have an inspiring figure at the club and that does not have to be a coach."

She is aware, too, that her son serves as a role model. There is a clamour around her as she dispenses Andy Murray sweatbands and T-shirts.

The smiles of a Monday in Stirling contrast with a Wimbledon Sunday when mother and son cried after an extraordinary final that the 25-year-old Scot lost against Roger Federer.

"He came very close, particularly in the first two sets, and he played some great tennis. He was obviously disappointed but he had to be reminded that getting there was a great achievement. He was playing against the best player of all time in the biggest tournament. He is very nearly there. There is lots to celebrate, lots to be proud of."

The chants of supporters inside Centre Court made it an emotional day for mother and son. "I have never seen those scenes or heard that in all my years at Wimbledon. 'He earned himself a lot of new fans. I hope it makes him even stronger."

She also gave a telling glimpse of how her son reacted to setbacks.

"Even when growing up, whenever he had what might be called a disappointing defeat he would always come back stronger. He lost in the final of the unofficial world under-14 championships in Tarbes in France. He had a match point, backhand, open court, and he put into the net and ended up losing the match. But it made him more hungry to win.

"Then he lost to [Marin] Cilic in the semis of the French Open juniors in 2005. He ought to have won that match but he said: 'Never mind, mum, back to London to practise on the grass for Queen's'."

She adds: "He will dissect that match with Federer, look at every shot, every percentage, whether first serves, break points won, whatever. He will take that information into training and hope to turn it round."

There is an obvious note of seriousness in all of that but the smile soon breaks out. An email beeps on her phone announcing that for the first time since 1991 four British women are in the top 100 in the world rankings.

The Fed Cup captain is delighted and she reflects on the trip to Israel earlier this year when her team attempted to qualify for the world group.

"The spirit was excellent and it gave us all a lot of energy for the games. Laura Robson had a roll-up darts board and a game called Pass the Bomb that had a ticker in in it that somehow managed to get through security and into Israel."

The smile comes back. Funny game, tennis.